Steam trap



Patented Aug. 23, 1938 vPA'IENT ori-ICE STEAM TRAP John F. McKee,Lansdowne, Pa., assignor to Yarnall-Waring Company, Philadelphia, Pa., acorporation of Pennsylvania Application March 17, 1934', Serial No.l716,099

`26 Claims.

Mv invention relates to steain traps and methods of adjustments of thetrap.

A purpose of the invention is'l to provide a steam trap that will be atonce small, light and inexpensive to manufacture and that willeffectively meet the needs of'service in that, while preventing 4steamdischarge, it will have large capacity for discharging water, foreliminating air when'rst turning steam into the trapped system and formaintaining the system -free from air and water. -A further purpose istoprovide for adjustment from theoutside of leakage rates to or from asteam* trap expansion chamber, thus controlling the temperature rangesand pressures at which the trap operates.

A further purpose is to provide a trap capable of use upon a wide rangeof steam pressures and. depending for its mostsuccessful operation upona ratio between the freedom ,of leakage of condensate past a piston andthe freedom of leakage through a bleeder port, one leakage into and theI A further purpose is to provide for axial move ment of a taperedpiston chamber. or tapered plug into which ya perforated piston valveloosely fits, or which loosely fits a leakage perforation, so as toadjust the ratio between freedom of leakage past the piston and thatthrough the perforafrom the exterior to vary the performance of a steamtrap.

vA furtherr purpose is condensate and/or air from a'steam system by atrap yat a rate lower than that at which condensate ordinarily forms, todischarge any accumulated excess of condensate fromthe systemperiodically at a higher rate than that at which it forms and to adjustthe periods of discharge and the rate of discharge while the trap isconnected for service.

A further purpose is to ensure uniform heating of a steam trap pistonand of the chamber into which the piston loosely ts so that theclearance tion, and to adjust the saidratio controllably v.tocontinuously, draw oilI pending case.

(Cl. 137-103) A ent forms of vmy invention, selecting forms, however,that are practical and eicient in operation, and which will illustratethe .principles involved.`

My invention relates not only to the methods or processes involved butto mechanism by which they may be carried out.

Figure 1 is a sectional elevation illustrating a desirable embodiment ofmy invention.

Figure 2 is a sectional view taken upon the .line 2--2 of Figure 1.

Figure 3 is a perspective view illustrating a detail of Figure 2.-

Figures 4 and 5 are sectional views generally similar to Figure 2, butillustrating modifications.

Like numerals refer to like parts in all figures. f

Steam systems, such as steam lines and steam devices generally, commonlycontain air and condensate. -The air. is 'ln the system when it isstarted up, and additional air enters the system in any one of manyways', as, for example, in the form of air dissolved in the feed waterto the boiler. Condensateis water produced whenever steam loses itslatent heat of vaporization. Both are undesirable.

My steam trap will remove both air and condensate with negligible lossof steam, normally operating continuously on condensate, keeping highpressure steam away from the-trap.

The present application shows asteam trap having a piston-controlled.valve with leakage e both past the piston and through it, first intoand then out of a control chambenformed by the piston-and the walls ofthe piston chamber. I'he present construction is thus of the samegeneral character as-is shown in mycopending application Serial No.674,253,1lled June 3, 1933, capable of operation exactly 'as the trapoperates which is shown'l in Figures 1-3 of that application, and

with the same purposeand benefits as are applicable to the constructionshown in these figures. The present invention provides in addition easeof construction without the same attention to the exact sizes of leakageparts and with adjustment of operating conditions, temperatures `andrates of ow while the trap is connected up not stated nor present in thestructure of these gures of the These differences are due to two mainfeatures. '-The one is that the chamber in which the steaml trap pistonoperates is here preferably tapered, altering the t of the piston ity ofthe size of one of the leakage ports (and thus their ratio), preferablythat port provided between the piston and piston chamber by movl ing thepiston chamber axially from the outside while the 'trap is in use, toadapt to the exact conditions of intended use.

In each of the different illustrated embodiments of my invention thetrap includes a hollow body l5 having an interior divided into an inlet.

space or compartment IS, an outlet space or compartment I? and a controlspace, chamber or compartment I8. A ported division wall I9 is locatedbetween the inlet and outlet compartments and a removable valve seat isshown.

'Ihe movable wall 2| of the control chamber is a narrow and preferablywabbly piston which carries a valve 22 controlling the :dow through thevalve port or passage 28.

' When slightly raised the valve as shown can have lateral movement.This permits the pistonto wabble and thus assists in scraping the pistonchamber wall by the piston to eliminate foreign matter and thus preventsticking.

In Figures 1-3 the control chamber IShas throttled inlet past the piston2d from the inlet compartment lli-and throttled -outlet at `25 by anaperture through the pistonand valve to the outlet compartment Il. InFigures 4 and y5 the inlet is through the piston and valve and theoutlet is past the piston.A .Y

'I'he inlet must not normally be large enough to admit condensate freelyas the valve willthen be held shut: nor should it pass condensate asfreely as the outlet. The outlet must be smaller than would be requiredto pass minimal conden- I sate. Different capacities are taken care ofby adjustment to open the valve at more frequent or less frequentintervals.

It will be noted that the annulus of leakage space past the piston andbetween it and piston chamber is very narrow in a radial direction,

much narrower than the diameter of the outlet,

so that any foreign matter which passes the piston passes out freelythrough the aperture.

IThe threads 2t and 27 are intended for pipe connections 2t and 29respectively, to a system requiring a trap to remove condensate von theone hand, and to a waste or hot well on the other. The expansion.chamber is located within a removable bonnet 3i! threaded to the bodyiat 3l.

The piston 2i of the hollow movable pistonvalve unit has a throttle fitwith the bore 32 of the cylinder within which the piston fits. Y

The clearance between the piston and the inside wall of the pistonchamber isV important as determining the ratio of freedom of inlet ow tofreedom of outlet flow to and from the control chamber. The piston-valveunit carries not only .the hollow conical valve 22 and the hollowconnection 33 between it and the piston but also a hollow stem 3dextending through the passage 23 and an impulse disc or flange 35located some distance beyond the seat member.l y T o the extent thus fardescribed this construction is identical with the construction ofFigures l-fi` of my application previously mentioned. The same bodyvalve seat and valve can be made interchangeable in the two.

From the presence of this disc or ange the trap would perhaps beclassied asv an impulse trap-and the disc is important-but the controlchamber and its adjunctiveleakage connections and adjustments arefundamental. The bonnet andthe piston chamber carried by the bonnet,with the connections between the piston chamber and the bonnet are quitedifferent.

"I'he most notable differences between the piston chamber of Figures 1-4herein and the cylinder of my application above, lie in the taper of thepiston chamber and in the spacing of the piston chamber from the bonnet.In the preferred form the inlet lto the expansion chamber is past thepiston at the outer periphery thereof and the taper enlarges the boreinside the piston chamber as compared with the size of the bore at theouter (open) end ofthe bore. 'I'here is here a distinct advantage, evenif the piston chamber be xed, in that the leakage inlet, the clearancebetween the piston andl the chamber interior then progressivelyincreases as the piston progressively moves'inwardly into the pistonchamber, i. e. as the valve lifts from its seat.

However, there ls a further and very considerable advantage'of -taperingthe piston chamber,`

whichever way it is tapered, when this is used -in conjunction withmechanism for moving the thus to adjust the relation between the freedomof leakage past the piston and the freedom of leakage throughthelpiston, avoiding, by the adjustment provided, the necessity. forcare in manufacture to make sure that the sizes of inlet and outletleakage passages are correct and bear the desired proportion. Themanufacturing tolerances 'for these two leakage paths are made much lesscritical. The same valve can thus be adjusted to meet dilerent operatingconditions as to steam pressure and variant quantities of condensate tobe handled or tempera'- tures at which it is to be discharged.

The fact that the volume of the chamber formed between the piston andthe closed end of the piston'chamber'is also varied does not interferewith securing a very nice adjustment of the ratios between the Vtwoleakages and the instantaneous values of the volume of the controlchamber.

The preferred form of bonnet, piston chamber and mechanism by which thepiston chamber is adjusted is shown in Figures 1 tov 3, and is asfollows:

The bonnetis made deep enough to permit it to carry the cup 36 as amovable member in it,

defining the piston chamber 3.1 as within this cup rather than by thewalls of the bonnet itself. The position of the'piston chamber iscontrolled by a bolt 38 rigid and preferably integral with the pistonchamber, which bolt is kerfed at 39 for engagement by a screw driver andis threaded at di) into the outer end of the bonnet so that turning ofthe bolt turns the piston chamber and at the same time advances orretracts the piston chamber with respect to the piston. The cup isretained in its position as ultimately set, by lock nut @l after whichthe cap d2 is threaded on the bolt so that finished surfaces G3 and Mupon the cap and the end of the bonnet seal to prevent escape of anysteam which may pass ybetween the threads. i l.

The piston chamber is spaced from the bonnet as at d5 so that thcondensate can surround the piston chamber and protect it vfrom contactwith control chamber.

the bonnet. The piston chamber'and Apiston are thusl maintainedat'substantially the same instantaneous temperatures throughout therange .of condensate temperatures and a Very small clearance between thepiston and piston chamber will be maintained with little danger ofsticking. Both the bonnet and the cap are hexed at 46, 46' respectively,so as to facilitate screwing them to place. 4

Assuming that the piston chamber is in fixed lowsz- When the system isstarted increase of pressure will cause the air present to pass outthrough the Very soon with the mounting pressure a mixture of relativelylow temperature water and air reaches the trap which mixture shifts thepiston and opens the valve, allowing the air and the first condensate toescape freely.

As the condensate discharges, high pressure steam comes nearer vto thetrap, and the conf densate temperature andthe pressure within thecontrol chamber both progressively rise, the valve closing, if there hasbeen proper adjustment of the valve, when temperature within the controlchamber is within a few degrees of the temperature corresponding to livesteam pressure, either just before or just after, steam reaches thelchamber.

The ratio between the area of the piston end (subject to the closingpressure of the control chamber) and the area under the valve exposed tothe back pressure beyond the valve largely controls the pressurerequired in the control chamber to close the valve. 'Ihe higher thisratio the nearer does the requisite control chamber pressure for closureapproach steam pressure andthe more critical becomes the need vfor anexactly rightre lation between the inlet and outlet areas respectivelyfor ilow into and out of the control chamber. With correct adjustment ofthis last ratio by suitable adjustment of the longitudinal position ofthe tapered piston chamber the fall in temperature of the condensatebecomes very'small after the valve has closed and before it opens again.By the tapered piston chamber structure it is possible to obtain goodresults not lonly with the ratio of 4 to 1 between the areas of, pistonand valve but with manyhigher ratios to obtain automatic opening andclosure of the valve at temperatures but a fewdegrees lower than steampressure temperature.

The valve is thus controlled by change of temperature of the waterimmediately at the trap, opening when the reduction of pressure in thecontrol chamber permits the pressureof the system (acting throughaccumulating condensate) to lift the valve and fluttering or closing ashotter condensate engages the piston and as the rush of condensate pastthe impulse disc forces the valve toward' closure. Wobbling of the valveassists in keeping it free from sticking. Taper of the piston chambergives progressive added pressure to reduce too fast or too much opening.through the open valve tends to hold the valve open.` The energy of theflowing) condensate acting uponl the collar', flange or disc 35 is usedto overcome this tendency to hold the valve open and thus to assist inclosing the valve. Observation shows that the valve remains partly open,fluttering, for long periods.

In the form' shown in Figures 1 3, with the A open end of the taperedpiston chamber at" smaller than the interior at 48 and with the positionof the tapered piston chamber` fixed,- as it will be afteradjustment-movement of the piston into the tapered piston chamberincreases the annular leakage area between the piston and the .taperedchamber walls with the advantage that with opening movement of the valvethere is a progressive increase in the chamber pressure because of theprogressive increase in the freedom of inletto the chamber without anycorresponding increase in the freedom of outlet.l This progressivelyincreasing chamber pressure with progressive opening of the valve causesthe valve to shift toward closure, eitherclosing or ilnding a positionof equilibrium with the degreeof its opening changing to accommodate thechanging supply of condensate which ows from the steam systemn and musttherefore beA taken care of.

Where the steam trap is of the type show n in my previous applicationabove referred to with a cylinder of uniform bore throughout therange ofpiston movement, the selection of a ratio between the diameter of thebleeder valve through the piston and operating valve and the annularspace for leakage between the piston and :the cylinder becomes highlyimportant and must represent a i' mean accommodating thev wide range ofpressures to be handled by the valve rather than a proportion which willgive maximum satisfaction at the `range jof satisfactory trap operation,permitting the trap to operate satisfactorily during the period of lowercondensate supply. For this reason it is better to havemerely normaltolerances between the outside of the piston and the inside cial work.This commercial work tolerance is a clearance so low that itis`desirable to guard against sticking. Slight difference in thediameter. makes a wide variation when the flt is intended to-b`e soclose. IIQ'here is trouble also in maintaining such aminimal spacingbecause of the fact that the piston heats up more rapidly than thepiston chambery causing binding and sticking due to the change intemperature accentuated by` the cooling of the piston chamber on theoutside. The first difficulty is overcome by the tapered piston chamberwhich does not require such initial accuracy but permits the t to be theyselector adjustably by longitudinal of the chamber in a closed positionfor commermovement of the piston chamber and the second dilculty istaken care of by making the4 piston chamber thin and spacing it from thebonnet so that the piston chamber is heated on both sides from the`condensate and has a chance to heat uniformly at the same rate as thepiston and to expand at substantially the same rate as the piston.

The spacing of the piston chamber from the bonnet allows the condensateto completely surround the piston chamber. This does not affect thetaper and could have been used withoutit. In the present case afterdetermining upon a taper which will give'a range of annular leakageareas about the piston suiicient to include satisfactory areas for' thedifferent pressures and condensate volumes to be handled the valve canbe installed and the selection of the particular annular leakage areaabout the`piston can be left to individual adjustment which interpretsthe adjustment in terms of satisfactory operation and in which the onewho makes the adjustment does not know and does not need to know thearea of annulus provided. y

Though the taper in the piston chamber is suflicient to make a quiteconsiderable difference in the size of the opening within the range oflongitudinal movement of the piston where the Vari-- ation in clearancefor lfluid passage is a. matter of thousandths of an inch, the slope ofthe piston chamber wall with respect to the outer perimeter of thepiston in the short distance represented by Athe thickness of the pistonas a disc is negligible so that the annular'passjage formed between thepiston' and wall` at any 'given time may be con-y the thickness of thedisc.

The square inlet edge to the annular passage (due to vthe substantialright-angle made between the nearly radial walls of the piston -and the1 cylindrical perimeter of the piston) make this annular orice a verypoor orice for the passage of passage water. 'Ihe annular orifice isthereforerelatively a bettery orifice for steam than for water.

As contrasted to this the discharge outlet through the piston is givenrounded edges', as seen at 25, Figures 1 and 2, with the result that thecoeiiicient of discharge for water is much improved while thecoeillcient of discharge for steam is little altered. It will be vseentherefore v compartment and keeping the valve open -for dischargewateru'p to a point where the temperature of the water entering thecontrol compartment is so high that the lar-ger proportion of steamflashing at its outlet retards the outlet and the pressure in thecontrol chamber is lifted, closing the valve. v

On the other hand, if live steam have access to the inlet compartment,by reason of discharge-of too large a proportion of the water therefrom,the live steam enters the control compartment with comparative ease, butdischarges therefrom with comparative difficulty, as compared with theconditions of water entry and discharge, resulting in the quick increasein the pressure within the control compartment, with correspondingimmediate closing of the valve.

Another factor relating to the operation is that with hot water(condensate) outlet through my valve there is avery much higher backpressure tending to hold the valve open than there is with steam outletthrough the valve. The back preswater the water than that due to steam,perhaps 2 to l1. The reduction in back pressure where there has beendischarge ofcondensate and steam has en tered the control chamberaifords a further protection when this excessive back pressure has beenrelieved, making it easier for steam in the control (expansion) chamberto close the valve.

It will be evident that the substantially square edging of the piston isvery desirable on the inlet compartment side of the piston, yi. e. thatside and tested. and which are practical on pressures from zero to 600pounds per square inch. It has been found that the device is fullyoperative with a. considerable range of vproportions of leakage .annulusabout the piston and outlet through the piston including for example aratio of 5/1000 difference between piston and piston chamber diametersto '16/ 1000 leakage aperture through the piston and operated to lowerpressures with ratios of 3/ 1000 to l12/1000. These are given as generalinformation only in view of the fact that the adjustment is made to suitthe individual conditions in each case. avoiding necessity for attemptedexact predetermined size of annulus I sure due to water outlet isconsiderably greater and also gives opportunity to suit to the exactpressures or to abnormal rate of condensation for the pressure.

It should be noted that in making the adjustment, moving the pistonchamber axially outwardly so as to make its walls more closely hug thepiston decreases the vapor ow into the control chamber and linnormaloperation, lowers the pressure within the control chamber for the samelwater temperature at the trap and makes the trap valve remain openuntil a higher condensate temperature in the control chamber is reachedat which the condensate will vaporize; while moving the piston chamberinwardly increases the water in the control chamber, increases thetemperature in the control chamber and closes the valve more quickly,

The adjustment by longitudinal movement of the piston chamber or rod inall of the forms adjusts the ratio between inlet and outlet controlchamber leakages and also varies the volume of the control chamber.Adjustment thus satisfies the composite of all of the changing factors.

The alternative forms illustrated in .Figures 4 and 5 have been shownfor the purpose chiefly of illustratingthe flexibility of my inventionand the fact that the piston can be tapered either way and the inlet canbe rom either end; also that the leakage can take place directly throughthe aperture at the middle of the piston and out through the pistonleakage or I'lltering first through the piston leakage and subsequentlyout through the aperture.

In Figure 4.1 have vshown a device which I regard as less desirable thanthat shown in Figures 1, 2 and 3 but which nevertheless is operative andwhich diiers from that of Figures 1-3 in three particulars.

The steam entrance and out? let are reversed with respect lto thedirections of Figure 1, the steam entering from the left of the gure andleaving at the right and all of it which passes through the controlchamber. goes through the valve iirst: the aperture through the pistonand valve is cleared and protected by a rod which also somewhat limitsthe wabbling of the valve,

- p and theldirection of taper of the piston chamber is reversed.

The trap body is the same. 'I'he combined valve and piston having thebody 33 is exactly like the valve and piston of Figure 3 except that theaperture 38' is considerably larger than the aperture of the valve 38and part of the aperture space is filled up by a rod 50 whichpassesclear through the element, and which, alternatively, may eitherrest as at 5| on the bottom of the interior of compartment Il, ofthe'trap, here the inlet compartment, andvt loosely at its upper endwithin a bore 52 in the bonnet or may be secured within the bore 52 andnot .touch at the bottom.v The purposes of the rod are to scour theinlet aperture so as not to permit clogging and to give the v requiredsize of leakage opening through the valve and piston without havingunobstructed entrance `space at any point radially large enough to allow-oreign matter to pass through which will not freely pass throughtheleakage spacelfromthe control compartment I8 out past the piston.

Because the inlet through the piston-valve is unchanged withpiston-valve opening movement vthe interior 35 of the piston chamber istapered reversely from'that shown in Figures 1 and 2 so as to are towardthe open end. This alters the cross section valve area ratio of inlet tooutlet in the same way as the opposite direction of taper in theconstruction shown in lligures 1,-3 but in.- stead of increasing theinlet as there, the oulet from the control chamber is reduced here asthe piston-valve lifts. It will be recognized that either form of taperpermits adjustment of the leakage space past the piston between it andthe piston chamber walls and thus permits exterior adjustment of theratio between this leakage space past the piston and the leakage spaceallowed through the piston. The valve flutters above its seat for a gooddeal of its operating time, upward movements of the valve causing.increase of pressure above it and downward .movements of the pistoncuttingf'ot the inlet to the contfl chamber or In all of the forms thetrap is assembled in the vgeneral position as shown with the pistonchamber at an intermediate point in itsadjustment. The trap is connectedinto the steam line, whether for initial "setting or in its position ofuse for adjustment to the needs of its service, and allowed to staythere until there has been sufficient accumulation of condensate for itto be set. The cylinder is adjusted to positionl where the trap isoperating just right, is locked in adju'ted positionfby the lock nut andthe cap is put inplace.

.Except for considerable variations in the rate of accumulation ofcondensate in different instal-- lations'the trap could be adjusted atthe factory for higher pressures without need for change.-

for very large or very low. rates of accumulation of condensate furtheradjustment is desirable with the valve in the place of intended use.

In general an inward adjustment of the piston!" chamber willprogressively increase the control' chamber inlet to outlet area ratiowhich in turn will progressively reduce the temperature at which thevalve will open with a progressive increase in the rate of dischargethrough the open valve. There will also be progressive increase in themaximum capacity of the trap. Such inward adjustment in the forms ofFigures 1 and 5 will increase the inletl cross sectional area andthereby somewhat increase the rate of continuous leakage through thelcontrol chamber, while in the form of Figure 4 the inward adjustmentwill lessen the outlet area and thereby decrease the rate of continuousleakage through the trap.

It will be evident that the provision for conthe piston chamber and withthe, impulse disc for valve closure to secure,- at one setting, aminimum continuous ow through the .trap consistent with t-her trapydimensions and commercial machine Shop tolerance, and an easyadjustment away from this setting to adapt the trap to operate ondiierent conditionsi and with only a very moderate increase in thecontinuous flow through the trap.

In view of my invention and disclosure variations and modifications tomee*I individual whim or particular need will doubtless become evidentto others skilled in the art, to obtain part or all of the benets of myinvention without copying the structure shown, and I, therefore, claimall such in so far as they fall within the reasonable spirit and scopeof my invention.

lHaving thus described my invention what I claim as new and desire tosecure by Letters Patent is:-

1. The method of adjusting a leakage connection in a steam trap havinginlet and outlet comjusting the control chamber wall axially withrespect to the valve seat thereby contracting or enlarging the sectionalarea of one of the leakage connections with respect to the 4sectionalarea of the other and altering the volume of the'control chamber for anyposition occupied by the piston.

2. The method of operating a steam trap having an outlet-valve-connectedpiston movable axially, separating an inlet compartment-from a controlchamber and having a leakage connectionfrom the inlet compartment to thecontrol. compartment between the piston and chamber walls andl a leakageconnection from the control chamber to discharge, which consists inpresenting condensate under steam pressure to the inlet compartment,thus causing condensate leakage past the piston between it and thepiston chamber and in varying the leakage past the piston with diilerentextents of valve opening by varying the diameter of the control chamberat the diilferent positions occupied by the piston. 1

3. The method of operating a. steam trap having anoutlet-valve-connected piston operating axially of a piston chamber,with the piston septhe control chamber to discharge, which consists inpresenting condensate under steam pressure to the inlet compartment,thus causing condensate leakage past the piston between it and thecontrol chamber, in increasing the sectional area of vthe leakageconnection past the piston with opening movement of the valve and forall movements of the valve adjusting the-sectional area of the leakageconnection past the piston in any given position by alteration of therelative position of piston and piston chamber along the axis of thepiston chamber, the operation with inlet chamber flow of condensatebeing to increase progressively the pressure within the control chamberas the condensate temperature progressively rises, as distinguished froma popping action in which successive accumulation of condensate at theinlet chamber successively shut off passage of steam to the controlchamber, the resultant reduction of pressure Within the control chamberpermitting the piston to lift suddenly opening the valve for an exhaustof the accumulated condensate.

4. In connection with a steam trap, comprising a body having outlet andinlet compartments, a control chamber connected with the inletcompartment, a piston in the control chamber and a valve connected withthe piston and cooperating with a valve seat between the inlet andoutlet compartments, and the said control chamber having a leakage inletbetween the piston and the chamber walls and a leakage outlet from thecontrol chamber into the outlet compartment, the art which consists inmaintaining the piston and both the inside and` outside of the controlchamber at substantially the same temperature by engagement ofcondensate with them and in varying the clearance ofthe piston in thecontrol chamber by reason of movement .of the piston axially withinl thecontrol chamber to vary leakage past the piston, increasing the ratio ofleakage inlet to leakage outletwhen the valve is open as compared withthat when the valve is closed.

5. The methodof securing the most desirable relation between thesectional passage areas respectively of leakage of fluid into andleakage of nuid from the control chamber of a steam trap having achamber the fluid pressure in which controls discharge of condensate bycontrolling the opening and closing of a valve between inlet and outletcompartments of the trap. and in which the control chamber is bounded bya pistonand by the sides and closed end of anA internally taperedcontrol chamber, which consists in admitting fluid into and withdrawingthe uid from the control chamber through leakage passages one of whichis the clearance between the piston and the tapered interior of thecontrol chamber and'in determining the clearance between the piston andthe control chamber initially by trying out the trap in a steam linewhile altering the position of the control chamber from the outside tochange the clearance between the Piston and the control chamber. f

6. 'I'he method p1' operating a steam trap having anoutlet-valve-connected piston operating axially 'cfa' control chamber,saidipiston separating an inlet compartment from a control chamber andhaving a leakage passage past the piston to the control chamber and aleakage paspartment comprising sage from the control chamber todischarge,

which consists in presenting condensate under steam pressure to theinlet compartment, thus causing condensate leakage past the pistonbetween it and the control chamber, in altering the ratio between theareas of inlet to and outlet from the control chamber with openingmovement of the valve and at the same time increasing the resistance todischarge ow through the valve by excessive opening movement, theoperation with the inletchamber flow of condensate being .to increaseprogressively the pressure within the control chamber as the condensatetemperature progressively rises, as distinguished from a popping actionin which successive accumulation oi condensate at the inlet chambersuccessively'shut bounded by a piston and by the sides and closed end ofan internally tapered piston chamber, the clearance space between thepiston and the tapered interior of the chamberproviding the passage forleakage into the control chamber and the leakage passage from thecontrol chamber comprising a passage through the piston and valve. whichconsists in adjusting the piston chamber axially so that with increasedValve opening there will be variation in the area of leakage past thepiston, causing the-pressure in the control chamber to rise more rapidlythan would otherwise be the case and tending to close the valve earlierthan otherwise, and in assisting closing movement of the valve by thepressure of uid passing through the valve. A

8. In a steam trap, a body having inlet. control and outletcompartments, the control cornlargely an internally tapered pistonchamber, a piston lying within the piston chamber, the piston completingthe control compartment, a valve connected vwith the piston andcontrolling the flow of fluid between the inlet and outlet compartments,there being leakage from the control compartment to discharge, and meansfor adjusting the piston chamber axially with respect to the piston forvarying the rate of leakage as between the inlet and outlet rates offluid flow.

9. A steam trap comprising a body having inlet and outlet compartments,an internally tapered piston chamber and a unitary member comprising apiston and a valve, the said member having -an aperture longitudinallyvthrough the piston and through the valve, the piston being loose in thepiston chamber, thus allowing 'leakage through the piston and valve andpast the piston and using the portion of the piston chamber beyond theend of the piston as a control compartment for the trap.

10. In a steam trap a body having inlet and outlet compartments andavalve seat between them, a combined thinpiston. and valve apertured toprovide leakage through both of them, an internally tapered pistonchamber within which the piston operates and with which the piston formsa control chamber, the piston tting loosely in the piston chamber toallow leakage past it and means for axially moving the tapered cylinderwith respect to the piston to adjust the looseness'of -the initial' litof the piston in the piston chamber.

11. In a steam trap a body having inlet and outlet compartments and avalve seat between them, a combined piston and valve apertured toprovide leakage through both of them, an internally tapered pistonchamber, open at one end, ywithin which chamber the piston operates andwith which the piston forms a control chamber,

the piston fitting loosely in the piston chamber to allow leakage pastit and the taper of the piston chamber giving greatest diameter at theopen end of the piston chamber. l 12. In a steam trap abody having inletand outlet compartments and a valve seat between them, a combined thinedged piston and valve apertured to provide leakage through both ofthem,' an internally tapered piston chamber closed at one end withinwhich chamber the piston operates and with which the piston forms acontrol chamber, the piston iltting loosely in the piston chamber toallow leakage past it, and the taper of the piston chamber givinggreatest diameter at the closed'end of the piston chamber.

13. The sub-combination adapted for use in a steam trap -comprising alongitudinally movable internally taperedpiston chamber, means for adjusting it longitudinally, an apertured 4piston iitting in said pistonchamber, movable therein and .having its clearance in said pistonchamber altered with relative movement .of the piston chamber andpiston, for any given piston position and an outlet valve controlled'bymovement of the piston and apertured in communication with the apertureof the piston.

14. In a steam trap, a body having inlet and outlet compartments and avalve seat between' them, a combined apertured piston and looselymounted valve engagingthe valve seat, the loose,-

ness of the mounting of the valve permitting wabbling of the piston,when the valve lsoft' its seat, the aperturing allowing leakage' throughthe piston and then through the valve, an internally tapered pistonchamber within which the piston operates and with which the piston formsan eX- pansion chamber, the piston tltting loosely in the piston chamberto allow leakage past it, and means for mounting the piston chamber soas to permit access of condensate to its exterior and interior and meansfor axially adjusting the piston chamber to vary the t between thepiston periphery and the piston chamber.

15. A steam trap having inlet and outlet compartments and a. passagebetween them, a valve seat in the passage, an apertured valve therein, adisc on the .valve adapted to move the valve toward closure with flow ofcondensate past the valve, an apertured piston connected with the valveand the piston aperture being in communication with the valve aperture,'providing leakage through them,.a piston chamber having a tapered' 16.In a steam trap a body having inlet and outlet compartments and a valveseat between them, a combined piston and valve apertured to provideleakage vthrough both of them,4 an impulse disc carried by the valve atthe part thereof farthest from the piston and an internally taperedpiston chamber within which the piston operates and with` which thepiston forms a control chamber, the outside of the piston chamber beingexposed to'the condensate so that it is heated concurrently with theheating of the inside of the piston chamber.

17; In a steam'trap a body having inlet and outlet compartments and avalve seat between them, a combinedpiston and valve apertured to provideleakage through both of them, an internally tapered piston chamberwithin which the piston loosely operates and with which the piston formsa control chamber and impulse means beyond the valve from the piston todraw the pistonto a position where the inlet to the control chamber isreduced by reason of flow of condensate through the valve. 18. In asteam `trap a body having inlet and outlet compartments and a valveseatbetween them, a combined piston and' valve apertured t0 provideleakage through both of them, a piston ychamber within which the pistonoperates and with which the piston forms a control chamber,

lthe piston having a thin edge/and affording 19.1In a steam 'trapa bodyhaving inlet and outlet compartments and a valve seat between them, acombined piston and valve apertured to provide leakage throughboth ofthem, an inter-I nally tapered piston chamber within which the pistonoperates axially and with which the piston forms a control chamber,there being inlet and outlet' fluid communication between the inletchamber and the control chamber and between the control chamber and theoutlet compartment, means for moving the piston chamber longitudinallyfrom the outside of the trap and means for mounting the piston chamberfree from the outer trap walls whereby condensate being trapped is freeeto surround and to enter the piston chamber and the temperature of thepiston, chamber and piston are equalized.

- 20. In a steam trap, a body having inlet and outlet compartments andan opening between them, a valve seat about the opening, an internallytapered piston chamber axially in line with the valve seat, means formovi-ng the piston chamber toward and from the valve'seat and a pistonunit comprising a .piston adapted to fit variantlyy in the pistonchamber with variant piston chamber positions, and an outlet valveconnected therewith, the unit being apertured to permit leakage throughit, and an impulse disc beyond the valve seat in the direction of 'iluidiiow and in the path of discharge through said valve, adapted torestrain the opening movement and assist in closing movement ofthe'valve.

21. vA valve bodyhaving inlet andoutlet compartments and a valve seatsurrounding an opening between the compartments, a.' bonnet connected`with ,the-'inlet compartment, Y a piston chamber in the bonnet,meansfor axially adjust'- ing the piston chaaunberl toward and from the uvalve seat and an apertured piston unit within the piston chambercomprising a piston, a valve connected with the piston, means in linewithy compartments, a unitary member comprising a piston and a valve,the said member having an aperture extending longitudinally through thepiston and through the valve and the valve adapted to engage the seat, arod inthe aperture adapted to guide thepiston and prevent clogging ofthe aperture and with respect to which rod the piston moves and wallsforming a. piston chamber surrounding the rod and loosely surroundingthe piston.

23. A steam trap body having inlet and outlet compartments and a valveseat between the compartments, a valve engaging the seat, a piston rigidwith the valve, both the valve and piston having apertures incommunication with each other, a rod in the piston aperture adapted toprevent clogging of the piston aperture and with respect to which rodthe piston moves, and a piston chamber surrounding the rod and looselysurrounding the piston, the rod being tapered and adjustable from theoutside to adjust the aperture opening and alter the extent of openingwith longitudinal movement of the piston.

24. A steam trap comprising a body having inlet and outlet compartments,a valve seatV between them and a bonnet connected with the inletcompartment, an internally tapered piston chamber within the bonnet,means for adjusting the piston chamber longitudinally with respect tothe bonnet, a piston in the piston chamber cooperating with the pistonchamber to form a gimme control chamber beyond the piston, the clearancebetween the piston and the piston chamber providing leakage between thepiston" and the piston chamber, a valve adapted to engage the valveseat, the piston and valve being apertured and a rod passing through theaperture in the piston and valve, the fit between the piston and thetapered piston chamber being altered by axial movement of the pistonchamber.

25. A steam trap comprising a body having inlet and outletcompartments,a valve seat between them and a bonnet connected with the inletcompartment, a piston chamber closed 'at one end and movable within thebonnet, means for adjusting the piston chamber longitudinally withrespect to the bonnet, a piston in the piston chamber adapted by itsclearance to provide leakage between the piston and the piston chamberinto a control chamber formed between the piston and the end ofthepiston chamber, a valve adapted t'o engage the valve seat, the pistonand valve being apertured and a rod passing through the aperture in thepiston and valve, thet between the rod and aperture being altered bytaper variation due to axial movement of the piston chamber.

26. A valve body having inlet and outlet compartments and a valve seatbetween, a bonnet connected with the inlet compartment, a piston chamberin the bonnet, meansv for axially adjusting the piston chamber towardand from the valve seat and an apertured piston unit Within the pistonchamber comprising a piston and a valve connected with the piston, meansin line with discharge through the valve seat adapted to urge the valvetoward closure and tapered means for affecting the size of the apertureby longitudinal adjustment of the piston chamber.

JOHN F. MCKEE.,

